"Miss Monochrome" is an original character design from seiyuu Horie Yui. In March 2012, she first used the "Miss Monochrome" character as a 3D virtual singer to sing her songs at her concert Horie Yui wo Meguru Bouken III ~Secret Mission Tour~. Later, the character appeared in a range of merchandise as well as in the social network game Girlfriend (Beta).

According to the setting, Miss Monochrome loves only the monochrome style, dislikes all kinds of color, and always dreams about changing the world into her favorite monochrome color.